<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>Title</title>
</head>
<body>
<div id="app">
  <input type="text" v-model="message">
  <input type="text" :value="message" @input="onChange">
  <h2>{{message}}</h2>
</div>
<script src="../vue.js"></script>
<script>
  const app = new Vue({
    el: '#app',
    data: {
      message: 'hello'
    },
    methods: {
      onChange(event) {
        this.message = event.target.value
      }
    }
  })
</script>
</body>
</html>
